A printed circuit board (PCB) is used to mechanically support and electrically connect electronic components using conductive pathways laminated onto a substrate. Several substrates, each with their own conductive pathways, may be bonded together to form a conventional multi-layer PCB. The conductive pathways formed onto one substrate may be connected to the conductive pathways formed onto other substrates using via structures. Holes are typically drilled from one substrate to another substrate then filled and/or plated with conductive material to foam the conventional via structure.
Electronic components are typically mounted on both sides of the conventional multi-layer PCB. Electronic signals traveling from a first electronic component mounted on a first substrate of the conventional multi-layer PCB may travel through the conventional via structure to reach a second electric component mount on a second substrate. The electronic signals travel through a first conductive pathway formed on the first substrate through the conventional via structure to a second conductive pathway formed on the second substrate. The conventional via structure attenuates power levels of the electronic signals passing from the first conductive pathway to the second conductive pathway and also reflects some of these signals back through the first conductive pathway. The reflection of the electronic signals back through the first conductive pathway is detrimental to the performance of the electronic circuit formed on the conventional multi-layer PCB.
Typically, conductive pathways routing the electronic signals at higher frequencies were limited to a single conductive substrate of the conventional multi-layer PCB. However, the conventional multi-layer PCB is becoming smaller in size requiring more than one substrate to connect electronic components. The conventional multi-layer PCB may have hundreds, thousands, and even tens of thousands of vias to route the electronic signals between the substrates of the conventional multi-layer PCB.
Thus, there is a need for a via structure to optimize passing of electronic signals from a first conductive pathway formed on a first substrate of a multi-layer PCB to a second conductive pathway formed on a second substrate of the multi-layer PCB that overcomes the shortcomings described above. Further aspects and advantages of the present invention will become apparent from the detailed description that follows.
The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.